A ripper is an apparatus having a downwardly projecting blade, carried at the outer end of a pivotal arm or bar, adapted to be forceably impacted into a surface and then dragged to rip or scarify the surface. Rippers are sometimes referred to as scarifiers. Rippers may be used to break up asphalt or concrete pavement, to loosen rocky soils, to loosen rocks and stones imbedded in the earth, and for other similar purposes. The blade is supported by a forwardly extending arm or bar carried by a tractor or other suitable vehicle. The arm or bar is adapted for upward and downward pivotal movement so that the blade carried thereby may be dropped toward the earth or road surface on which ripping or scarifying work is being done.
The ripper blade is held in place at the end of the arm or bar disposed through a slot, which is called the "shank pocket". The apparatus is of heavy weight construction adapted for rugged use. For example, a ripper blade may be six feet or more in length, fifteen to twenty inches in width, and three to four inches in thickness. The blades are formed of steel, and consequently are of considerable weight. The arm or bar which supports the blade is often called the tool bar, and the auxiliary equipment for support and movement of the tool bar and blade are also of strong, heavyweight structures.
The shank of each blade is disposed through the shank pocket at the end of the tool bar, or a head carried thereby, and held in place by one or more cross pins. Since manufacturing tolerances are not close, considerable wear occurs between the blade and the tool bar or head through which the shank pocket is formed. The tendency for wear to occur has heretofore required fairly frequent replacement of the blade and of the tool bar or head, at considerable expense, and requiring considerable downtime for the replacements. This invention seeks to minimize wear between the blade and shank pocket, and to minimize the effect of such wear by minimizing equipment replacements as a result thereof.